The Acantharia-Phaeocystis symbiosis: an investigation of eukaryotic photosymbiosis and its ecological role in oligotrophic surface water

在2019财年，我完成了博士论文和论文答辩。我在加州的海洋科学会议上把我论文的最后一章作为海报展示出来。此外，我提交了3篇第一作者手稿供出版;它们正在审查中，并作为预印本在bioRxiv上公开提供。本章研究了共生的棕囊藻（Haptyophyta）的基因表达，而生活在紫茎泽兰（Rhizaria）的主机。我对单个棘皮动物宿主进行了单全栖生物RNA测序。然后，我对来自两种培养的棕囊藻物种的3个生物重复进行了RNA-seq，我用它们来创建参考转录组并绘制来自全生物的共生体转录本。然后，我对这两种共生体进行了差异表达分析。结果表明，共生菌上调光合作用和基因表达，但下调DNA复制和细胞周期进程。重要的是，共生体基因表达并不表明共生体是营养有限的，这是宿主用来限制共生体细胞分裂的常见方法。相反，宿主必须部署一种营养独立的控制机制。

During the fiscal year 2019 I completed my PhD thesis and thesis defense. I presented my final thesis chapter as a poster at the Ocean Sciences Meeting in California. In addition, I submitted 3 first author manuscripts for publication; they are under review and are openly available as preprints on bioRxiv. The chapter investigated gene expression in symbiotic Phaeocystis (Haptyophyta) while living inside Acantharian (Rhizaria) hosts. I performed single-holobiont RNA-seq with individual acantharian hosts. I then performed RNA-seq with 3 biological replicates each from two cultured Phaeocystis species, which I used to create reference transcriptomes and map symbiont transcripts from the holobionts. I then performed differential expression analyses for the two symbiont species. Results showed that symbionts upregulated photosynthesis and gene expression, but down regulated DNA replication and cell cycle progression. Importantly, symbiont gene expression did not suggest that symbionts were at all nutrient limited, which is a common method hosts use to limit symbiont cell division. Instead, hosts must be deploying a nutrient independent control mechanism.